During the last several years, there has been much activity in developing pressure sensitive adhesive, moisture vapor permeable wound dressings, bandages, and drapes for use in the medical field. It has been found that these moisture vapor permeable, pressure-sensitive adhesive dressings provide an improved surgical covering or bandage which speeds the natural wound healing process, while also protecting the wound site. In general, the wound dressings, bandages and surgical drapes allow water vapor to escape from a wound site while preventing liquid water from either entering or escaping from the site. In addition, bacteria is also prevented from passing through the wound dressing, thereby protecting the wound site from bacterial invasion.
Typically, these wound dressings, bandages, and surgical drapes all comprise a membrane layer which incorporates the desired physical characteristics to attain the moisture vapor permeability while preventing liquid water and bacteria from passing through the membrane. In addition, one surface of the membrane incorporates an adhesive which provides the desired pressure sensitive adherence for securing the membrane to the wound site and retaining the membrane in the desired position.
Although moisture vapor permeable, adhesive membranes have been widely recognized and accepted, with many competitive products being brought to the marketplace, all of these products have suffered from the same common deficiency. The principal problem is the difficulty users experience in handling and applying these prior art membranes to patients.
Moisture vapor permeable, pressure sensitive adhesive membranes are typically applied to a patient as a flat sheet, ranging in size from a few square inches to one or two square feet. In order to achieve the desired results, these moisture vapor permeable, pressure sensitive adhesive membranes are extremely thin and pliable. In this way, the desired permeability is provided and membranes are able to conform to the shape of the patient's body or skin. Unfortunately, this also causes the membranes to be extremely limp and difficult to handle.
In order to protect the adhesive surface, as well as allow the membranes to be easily handled prior to use, most prior art membranes incorporate comparatively heavy or thick release sheets or supporting or backing sheets. However, once the release or backing sheet has been removed, as is conventionally done prior to applying the adhesive membrane to the patient, great difficulty is encountered by the user, since the adhesive membrane is now unsupported and tends to stick to itself. As a result, most moisture vapor permeable, pressure-sensitive adhesive membranes require two individuals to apply the membrane to the patient, in order to assure and prevent the membrane from being so limp as to stick to itself and become unusable. These conventional prior art membranes are typified by Hodgson U.S. Reissue Pat. No. Re. 31,887 and the prior art references cited therein.
In an attempt to provide a system for applying these membranes to patients by one person, many prior art systems have been developed which provide a reinforcement or support means for the membrane in order to assist in the application of the membrane to a patient. These prior art systems include mechanical reinforcing layers such as foam, or other stiffening means, as well as removable layers of paper or cardboard, which assist in supporting the membrane during its application and are then removed once the membrane is in place. Furthermore, handles, both rigid and flexible, have been employed in order to further assist the operator in applying these membranes. The following U.S. Patents typify these prior art systems: U.S. Pat. Nos. 4,372,303 and 4,374,520.
Although these application and handling problems have existed for several years, no prior art system has been developed which achieves a readily dispensible, flat layered, vapor permeable, pressure-sensitive adhesive membrane which can be easily handled by a single individual and applied without difficulty. In general, the prior art systems which have been developed require the incorporation of additional support layers or stiffening layers to the membrane itself, typically on a non-adhesive surface thereof. However, these systems suffer from a tendency to degrade the quality of the membrane, as well as introducing extra material which may interfere with the healing process or with the visibility of the wound during its healing. Furthermore, in other such systems, the operator is faced with additional steps of removing the support or stiffening layer once the membrane has been in place, as well as the cumbersome nature of having to apply the membrane with this stiffening layer in place.
Therefore, it is a principal object of the present invention to provide a moisture vapor permeable, pressure-sensitive adhesive membrane which comprises a membrane layer incorporating reinforcing means therein which provides a membrane which is both inherently flexible, for application to the patient, and also sufficiently stiff to prevent the membrane from being limp and overly pliable during application.
Another object of the present invention is to provide a moisture vapor permeable, pressure-sensitive adhesive, reinforced membrane having the characteristic features described above which is easily used by a single individual and allows all reasonable sizes to be quickly applied to a patient without having the membrane stick to itself.
Another object of the present invention is to provide a moisture vapor permeable, pressure-sensitive adhesive, reinforced membrane having the characteristic features described above, which allows a rapid, easy, trouble-free application of the membrane to the wound site, regardless of the size, shape or length of the membrane.
A further object of the present invention is to provide a moisture vapor permeable, pressure-sensitive adhesive, reinforced membrane having the characteristic features described above which also assures complete sterility of the membrane for surgical use.
Another object of the present invention is to provide a moisture vapor permeable, pressure-sensitive adhesive, reinforced membrane having the characteristic features described above which prevents unwanted membrane stretching, while also providing an inherent visual indication to the operator when the membrane has been stretched beyond a satisfactory, acceptable limit.
Other and more specific objects will in part be obvious and will in part appear hereinafter.